Ron Paul supporters know he has little chance of becoming the next president, but they say his third bid for the job is about more than winning the GOP nomination or the White House — it’s about guiding the political landscape beyond the Republican-Democrat duopoly that’s controlled Washington for more than a century.

The man who in his 2008 bid was dismissed as a sideshow has emerged this year as the prophet of libertarian-leaning conservatives and tea-party supporters alike and has come to define the burgeoning coalition that preaches lower taxes, global retrenchment and more modest use of federal powers here at home.

“He is John the Baptist in that he is founding the call for what will be fulfilled in American politics within the next decade for sure,” said Nick Gillespie, editor of Reason magazine and a libertarian icon. “And for God’s sake, it is horrible to talk about political candidates as John the Baptist or Jesus for any number of reasons, including that one ended up with his head on a platter and the other nailed to a cross.”

After years in the political desert, torn between Democrats’ social liberalism and Republicans’ economic conservatism, Mr. Gillespie and fellow believers say the two major political parties are showing they’ve run their course as voters flee in search of the new kind of politics that Mr. Paul embodies.

Mr. Paul, in an interview with The Washington Times, said he hopes that is the case because the two major parties essentially have become one.

“Although the rhetoric might vary, they’ve been one party,” Mr. Paul said. “They both support the same foreign policy, the same monetary policy, the same domestic welfare policy — regardless of what they claim they believe.”

Becoming mainstream

Mr. Paul first ran for president in 1988 on the Libertarian Party ticket. In 2008, he sought the GOP nomination. Both times, his campaign fizzled.

His supporters, and he himself, say this time will be different.

“The issues are completely different and have come in my direction,” Mr. Paul said. “People are tired of the war. They understand the financial situation is dire, and those are things I have been talking about for so long. Now they have become mainstream issues, and even the Federal Reserve is something that a lot of people are talking about.”

“The magnificence of what is happening right now,” he said, “is they are starting to pay attention.”

Mr. Paul still faces a steep climb, and libertarian leaders say parts of the Republican Party will marginalize Mr. Paul, in part, because he says the 10th Amendment delegates decisions about whether to legalize drugs or abortion — which he opposes — to states.

“Polite society has agreed on a set of actually pretty insane policies that are christened as the status quo, and people who talk and insist on talking about stuff that is outside of that are treated as crazier than they actually are,” said Matt Welch, who co-authored with Mr. Gillespie “The Declaration of Independents: How Libertarian Politics Can Fix What Wrong With America.”

Mr. Welch and others, though, concede that Mr. Paul’s biggest strength — a strict adherence to principle that’s made him a libertarian hero — also represents his greatest weakness: the inability to see that the perfect is sometimes the enemy of the good.

“Ron Paul is, undoubtedly, ideologically committed to pro-growth, limited-government policies,” said Chris Chocola, president of the fiscally conservative Club for Growth and a former Republican congressman from Indiana, in a recent breakdown of Mr. Paul’s record. “But his insistence on opposing all but the perfect means that under a Ron Paul presidency, we might never get a chance to pursue the good, too.”

Mr. Paul has experienced a dramatic political turnaround since his 2008 presidential campaign, when pundits wrote him off as little more than a rabble-rouser, and Republicans generally dismissed his calls for a return to the gold standard, ending the wars in Iraq and Afghanistan, and auditing the Federal Reserve. But things swung in Mr. Paul’s favor in 2009 after the tea party emerged, rallying around the same small-government message that the Texas Republican had touted long before it became the chic thing to do on Capitol Hill and the campaign trail.

He opposed the No Child Left Behind education law in 2001, Medicare Part D prescription-drug benefit in 2003 and the TARP bailout in 2008 — all George W. Bush-led efforts backed by current GOP leaders, including House Speaker John A. Boehner, House Majority Leader Eric Cantor and Sen. Minority Leader Mitch McConnell. He also was one of three Republicans in 2001 to vote against the Patriot Act and one of six Republicans in 2002 to vote against military action in Iraq.

“He’s been saying the emperor has no clothes for a long time, and he has just been seen as a pariah or a nut case or a cynic, and I think people have been trained or indoctrinated their whole lives to be patriotic and blindly believe the government does the right thing,” said New Hampshire state Rep. Mark Warden, a libertarian. “But sometimes it takes an outsider who sees what other people don’t.”

Third but not out

Now, with the country facing a $14.3 trillion debt and the public growing tired of the wars, the GOP presidential field — which Mr. Paul says represents different variations of the status quo — is borrowing his 2008 campaign playbook by calling for a return to the Constitution, deep spending cuts and a rethinking of how the U.S. military is used.

Most polls of declared candidates place him third in the GOP field, behind former Massachusetts Gov. Mitt Romney and Minnesota Rep. Michele Bachmann. His latest fundraising report, meanwhile, placed him in a tight battle for second in the money chase after pulling in $4.5 million during the three-month period that ended in June.

On Tuesday, Mr. Paul’s chances in Iowa received another boost after he received a ringing endorsement from Corey Adams, chairman of the Story County Republican Committee, which covers the city of Ames, home to the much-anticipated Aug. 13 straw poll.

If this is the 75-year-old’s last presidential campaign, it raises the question of who will carry the torch when he bows out. Some say it would be his son, Rand Paul, the freshman senator from Kentucky who flirted with a presidential run before his father entered the race. Others point to former New Mexico governor and presidential candidate Gary Johnson, who was the leading libertarian in the field before the elder Mr. Paul entered the race.

“Of course, you always run to win, and I have lost some races, but I never felt like it was wasted effort because my goals in life have always been not to seek power, but certainly not to shy away from having influence. So, as long as there is a way to present some views that influence people, I get some satisfaction out of that.”